[Gasification] the most important thing (quite possibly) > i've learned to date

[Rolf Uhle]

Ken,
I once made a little experiment of torrifying granulated biomass with exhaust 
heat of a Lister indirectly .
I found it working all right, the temperatures adequate, but the biggest issue 
are probably the tarry (condensable) fumes driven out.
They would also be present in a direct exhaust system and have to be dealt 
with.
I guess you don't want to vent them off. They are noxious and they mean money 
and energy.
I led them into the Lister's intake and they burnt away nicely with the WVO 
diesel, but only for a short time. I guess on a longer base I would find the 
typical valve problems.
I still want to persue this way - just no time.

See you in Zellingen next WE ? 
The GEK has seemingly arrived.

Rolf




Am Dienstag, 19. Oktober 2010 08:54:58 schrieb Ken Boak:
> Andy,
>
> I'd also like to start a discussion about direct contact of the wood chips
> with the exhaust gas.  A pre-processing reactor that cooks the chips a
> little batch at a time then dumps them into the main gasifier reactor, via
> auger feed. As you say a "just in time" pipeline flow of pre-cooked, pre-
> heated reactants.  Water can be added if necessary as steam.
>
> Clearly the wood will become torrified, and the exhaust gas stream will
> drive off and purge the wood fuel of moisture and volatiles, whilst raising
> the temperature of the fuel considerably.  There will also be an increase
> in fuel energy density.
>
> If diesel exhaust was used (I'm thinking of a dual fuel Lister being
> started up on diesel to raise process heat and provide mechanical and
> electrical power for starting up gasifier), this will contain between 8%
> and 17% unused oxygen, and around 80% nitrogen.  Would the O2 be of
> sufficient quantity to cause partial oxidation of the fuel and possibly
> more heat?
>
> If the exhaust is from a woodgas engine - it will again be around 80%
> nitrogen, plus CO2 and CO.   If this relatively inert hot gas is used to
> purge the woodfuel of all moisture and volatiles - is the resultant off-gas
> ever going to have sufficient combustible constituents that it could be
> ignited in any sort of air fed burner - or is the nitrogen loading just too
> high?
>
>
> Thoughts appreciated,
>
>
>
> Ken
>
> On 19 October 2010 02:13, andy schofield <scothebuilder at hotmail.com> wrote:
> > Jim,
> >
> >    Pushing calories around in the DTU graphic model, I find moving heat
> > into the fuel is indeed the best use, for loose BTUs.
> >  In practice, heat transfer into wood is not easy because of limited
> > conduction and radiation, and zero convection in a mound of fuel.
> >  The GEK method is like stir-frying vegetables in a wok; forcing
> > convection. As each particle, contacts the walls of the pyrocoil; they
> > cook.
> >
> > Someday I want to attempt direct contact of the wood with engine exhaust
> > gas, after solving a certain sealing problem.
> > A "just in time" inventory of heated wood; roasted to perfection.
> > It is a shovel ready project.
> >
> > Looking forward to your findings.
> >
> > Andy
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > Gasification mailing list
> >
> > to Send a Message to the list, use the email address
> > Gasification at bioenergylists.org
> >
> > to UNSUBSCRIBE or Change your List Settings use the web page
> >
> > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioen
> >ergylists.org
> >
> > for more Gasifiers,  News and Information see our web site:
> > http://gasifiers.bioenergylists.org/